1. Field Of The Invention
This invention relates to apparatus used for placing a filter screen adjacent a well formation for gravel packing around the screen, and more particularly, to a gravel packing apparatus having a valve actuated by a stinger for pumping gravel through a tubing string into a well annulus adjacent the filter screen, and further allowing recirculation above the apparatus and production through the apparatus.
2. Description Of The Prior Art
Most gravel packing operations utilize a retrievable packer having means for pumping gravel therethrough to a well annulus around a filter screen positioned below the packer. These retrievable packers are relatively complex and the procedure of setting and unsetting is lengthy and expensive. The time and cost associated with such packers is a particular problem with low fluid level, marginal wells. The present invention solves this problem by providing a less expensive gravel packing apparatus which is made more simple to operate. The packer of the present invention includes an open central passageway therethrough so that the packer may be left in the well bore and production fluids simply flowed through it after the gravel packing operation. A stinger is used to temporarily close the central passageway and actuate a valve for pumping the gravel. The stinger is also used to close the valve and allow reverse circulation above the packer while maintaining the central passageway closed.
Another problem with prior packing operations using retrievable packers is that residual pressure in the well formation may blow out the gravel pack before a production packer or liner seal can be installed. The present invention solves this problem since the packer remains in place.
The gravel packing apparatus of the present invention is a modification of the EZ Drill SV.RTM. squeeze packer manufactured by Halliburton Services and disclosed in Halliburton Services Catalog No. 41, page 4009. The EZ Drill SV.RTM. squeeze packer is used for cementing operations and does not have a central passageway therethrough. This previous packer is actuated by a setting tool having a central opening therethrough. The EZ Drill SV.RTM. squeeze packer is not usable for a gravel packing operation as is the present invention.
Because the valve in the present invention may be opened and closed as desired, and because the packer remains in the well bore, remedial gravel packing around the filter screen is easily accomplished by running the stinger back in the hole. Running in another packer and going through the steps of operating it are avoided. Also, the present invention is unlike previous apparatus which include valve systems which cannot be reactuated. Finally, the apparatus of the present invention may be employed to place a screen, without subsequent gravel packing, adjacent a formation susceptible to breakdown during production, to prevent formation fines and other debris from obstructing and clogging tubing, pumps, valves and other production equipment.